Historically, malaria infections were controlled with quinoline-based alkaloids from the cinchona tree, particularly quinine. Insufficient supplies of quinine and the need to protect troops fighting in malaria-endemic regions fueled researchers to discover synthetic quinoline-based antimalarial agents. This effort led to a series of antimalarial compounds including chloroquine which has been the mainstay of antimalarial therapy since its introduction in 1945. Parallel medicinal chemistry efforts in the 1940s led to clinical evaluation of several phenolic Mannich bases as potential malarial agents.
However, the emergence of drug resistant strains of Plasmodium has caused many of the safest and least expensive antimalarial drugs to lose their effectiveness in many areas of the world. Therefore, there is a continued need to discover and develop antimalarial agents that are effective against new and old strains of Plasmodium. 
The present invention relates to aminoalkylphenols, compositions containing an aminoalkylphenol as the active ingredient and methods of treating malaria. The compounds of this invention are antiprotozoal agents effective in vivo and in vitro against protozoa of the genus Plasmodium (P. falciparum, P. bergei, etc.), the infectious agent responsible for malaria. The compounds of this invention are phenolic Mannich base derivatives, a class of chemical substances that have been intensely studied for many years for their antimalarial properties. See Burckhalter, J. H., et al., J. Am. Chem. Soc., 1946 Vol. 68, 1894-1901, and 1948, Vol. 70, 1363-1373, Duncan, W. G., et al., J. Med. Chem. 1969, 12, 711-112, and F. Y. Wiselogle, Ed.; Survey of Antimalarial Drugs, 1941-1945, Vols. I and II, Edwards Bros., Ann Arbor, Mich. Aminoalkylphenols are also discussed U.S. Pat. No. 3,794,734, issued Feb. 26, 1974 and Stokker, G. E., et al., J. Med. Chem. 1980, 23, 1414-27.